I really don’t like Captchas, the squiggly words that many websites use to protect forms from spam bots. Unfortunately, sometimes they are the only thing that can protect a site from clever spammers.
Yesterday I heard a great story about reCaptcha, captchas that are used to crowd-source digitizing of old print books and newspapers on NPR. If you have ever tried to use a scanner with OCR, you know that it can be pretty hit or miss.
It’s the brainchild of Luis von Ahn, a computer scientist at Carnegie Mellon University in Pittsburgh, who helped develop another commonly used Web security system. That one, called CAPTCHA, will allow people to access a Web site only if they prove they are human — and not a spammer’s computer — by typing in a sequence of letters or numbers that appear on the screen in a distorted or garbled image.
According to the story, 1.3 billion words have been digitized this way!
I am willing to put up with the pain of filling out a captcha if I know it is at least helping in some small way.
Now at CivicActions we shy away from using captcha due to usability and accessibility issues. Recently we have begun using Mollom on some client sites. Mollom first checks if a post seems spammy before forcing a user to enter a captcha. Mollom does not use reCaptcha though, it would be nice if it did.